Problems with HP PSC 750 all in one

I just spent a ton of money on a 15 and 78 ink cartridge only to have the machine not print. How do I force the printer to print? Why does a cartridge need aligned? How do I by pass this? How do I force the printer to print? I would't have to do this if HP would stop ripping people off with the price of ink. I have a deskjet 1000 I purchased to replace the PSC 750. When the piece of junk works I only got about 50 pages from the 61 ink cartridges. A lot of times the paper wouldn't feed. The worthless printer would just say it's out of ink. I just can't believe the gull of HP talking about their eco highlights. Just were do these dummies think the printers go when they are out of ink. They actually want $31 for two HP 61 cartridges. I paid $29 for the printer!